NFL players worry about leg injuries, especially to their knees, more than head injuries, according to a USA TODAY Sports survey. Letter to the editor:

One critical factor contributing to pro football's much publicized health problems is the greater size of today's players. They're parlaying such great bulk and speed, the concern is that the physics of impact may be outstripping the body's ability to tolerate it.

Fixes for the physical carnage are likely to be expensive and complicated. But has anyone considered weight caps for the various positions? For today's 300-pound linemen, for example, install a limit and step down by 10 pounds yearly until the top allowable weight is perhaps 260. Downsize similarly for other positions.

Boxing has controlled competition by weight, and scholastic wrestling has as well. Tinkering with football's physics might be worth considering, too.

Tom Gregg; Niles, Ill.

Comments from Facebook are edited for clarity and grammar:

A knee injury could end your season or career right now. A head injury could ruin your life later. Just as with smoking, often right now wins over later on (although it is possible to be concerned about the two things at the same time).

However, players should remember that with football, the rest of your life will last much longer than right now.

— Steve Evets

Regardless of whether it's a head or knee injury, how about players take some of the worry out of the equation and put more of those millions away just in case they do get injured?

— Howard Ross

The players should set up a fund financed by a percentage of their salaries to help cope with the consequences of injuries they suffer and cause each other. How well they are covered would be up to them.

Playing a violent contact game, where the purpose is to collide with players multiple times an hour and violently knock down opponents, is high risk. Participating is a personal choice, and personal responsibility should be taken for the results.

— James W. Davis

Your head is more important than your knees. It's pretty obvious players hit a lot harder now with so many 300-pounders, and some really don't care if the opponent gets plastered.